BAI GIANGC LU CHATPGS.TS. LE SONG GIANGBm C LU CHAT P. 304 B4TRNG AI HOC BACH KHOA Tp HCM

Cac thong tin can bietTai lieu :Giao trnh C lu chat (Bm. CLC)Bai tap C lu chat (LS Giang & NT Phng)

anh gia mon hoc: trac nghiem, e m (c xem tai lieu)Kiem tra 15 (10%) : C2Kiem tra 45 (20%) : C1 C3Kiem tra 15 (10%) : C4Thi cuoi ky 90 (80%): C1 C4

Chng 1. M AUnh ngha, oi tng va phng phap nghien cuCac tnh chat vat ly cua lu chatLc tac dung trong lu chat

1. NH NGHA MON HOC, OI TNG VA PP N.CU (1/2)1.1 nh ngha mon hocC Lu Chat: mon khoa hoc thuoc lnh vc C hoc nghien cu chuyen ong va can bang cua chat long, chat kh.

C hoc co ien

1. NH NGHA MON HOC, OI TNG VA PP N.CU (2/2)1.2 oi tng nghien cuChat long va chat kh.Tnh chat:Tnh chay-> Chat chay c -> Lu chatTnh khong chu lc cat, lc keoKhac biet gia chat long va chat kh la tnh nen c, nhng ch khi van toc u ln (V > 0.3a).-> Kh ong lc hoc: cho chat kh nen c

1.3 Phng phap nghien cuBai toan C lu chat

Phng phap giai: - Phng phap giai tch - Phng phap th nghiem

2. CAC TNH CHAT VAT LY CUA LU CHAT (1/3)2.1 Khoi lng rieng ()Khoi lng rieng: la khoi lng cua mot n v the tch lu chat

Trong lng rieng: Ty trong:

2.2 Suat an hoi (E)Suat an hoi ac trng cho tnh nen c cua lu chat:

oi vi chat kh: s dung phng trnh kh ly tng

.lngNcK.khT.ngan, kg/m31000 1,228 13,6.103, N/m39,81.10312,07133.103

2. CAC TNH CHAT VAT LY CUA LU CHAT (2/3)2.3 o nht (, )ac trng cho ma sat gia cac phan t lu chat trong chuyen ongnh luat Newton ve ma sat:

o nht ong hoc: Hai loai lu chat: lu chat Newton va lu chat phi Newton

.lngNcK.kh, poise1.10-21,8.10-4, stoke0,010,15

2. CAC TNH CHAT VAT LY CUA LU CHAT (3/3)2.4 Sc cang be mat ()

2.5 Ap suat hi bao hoa (pV)Ap suat hi: la phan ap suat cua chat kh do cac phan t hi gay ra.Ap suat hi bao hoa: ap suat hi trang thai ma qua trnh bay hi va ngng tu can bang (bao hoa)Hien tng sui va v bot hi:sui bot -> t oan chan khongv bot -> kh thc

3. LC TAC DUNG TRONG LU CHAT (1/2)Lc tac dung ch duy nhat lc phan bo va c chia thanh 2 loai:Noi lcNgoai lcNgoai lc gom lc khoi va lc mat3.1 Lc khoinh ngha: La ngoai lc tac dung len moi phan t cua the tch lu chat va ty le vi khoi lng lu chat.Thong so: - vector cng o lc khoi.

V du:Trong lc:Lc quan tnh:Lc ly tam:

3. LC TAC DUNG TRONG LU CHAT (2/2)3.2 Lc matnh ngha: La ngoai lc tac dung len the tch lu chat thong qua be mat bao boc va ty le vi dien tch be mat.Thong so: - vector ng sat.

V du: - Ap suat - ng suat ma satTensor trang thai ng suat

3. LC TAC DUNG TRONG LU CHAT (2/2)ng suat tren mat bat ky:

Khi

Chng 2. TNH HOC LU CHATAp suat thuy tnhPhng trnh vi phan cua lu chat tnhLu chat tnh trong trng trong lcTnh tng oi

1. AP SUAT THUY TNH (1/2)1.1 nh nghaTensor ng suat trong lu chat trang thai tnh:

Va la tensor cau:=> Ch can 1 gia tr la u ac trng cho trang thai ng suat va no c goi la ap suat thuy tnh.

1.2 Tnh chatAp suat thuy tnh tac dung thang goc va hng vao ben trong be mat chu lc.Gia tr cua ap suat thuy tnh khong phu thuoc vao hng cua be mat chu lc.

1. AP SUAT THUY TNH (2/2)1.3 Cac loai ap suatAp suat tuyet oi (pt)Ap suat d (pd, p):pd = pt - paAp suat chan khong (pck):pck = pa - pt

1.4 n vTrong he SI: N/m2Trong cac he khac:1at = 1kgf/cm2 = 10mH2O = 735mmHg = 9,81.104N/m21Pa = 1N/m2.

2. PHNG TRNH VI PHAN CUA LU CHAT TNH (1/2)2.1 Phng trnh EulerXet phan t lu chat:Ngoai lc tren phng x:Lc khoi: dxdydzFx

Lc mat:

Phng trnh nh luat II Newton cho phan t =>

hay

2. PHNG TRNH VI PHAN CUA LU CHAT TNH (2/2)2.2 Tch phan phng trnh EulerNhan phng trnh Euler cho vector vi phan chieu dai :

Ton tai ham the U cua lc khoi F:

Rut ra phng trnh:

Trong trng hp =const:

(C - hang so tch phan)

3. LU CHAT TNH TRONG TRNG TRONG LC (1/8)3.1 Phng trnh c ban cua thuy tnhTrng trong lc co:Chon he truc toa o vi truc z hng thang ng len tri:

=> Phng trnh c ban cua thuy tnh:

3.2 Phng trnh kh tnh.S dung phng trnh kh ly tng p=RT cho trong phng trnh Euler:

Trong tang bnh lu (z11km): T=T0-Lz

Trong tang oi lu (z>11km): T=T1=-56.50C

3. LU CHAT TNH TRONG TRNG TRONG LC (2/8)3.3 Ap dung phng trnh c ban cua thuy tnha. Ap keAp ke o ap tuyet oi

Ap ke o ap d

b. Mat ang apnh ngha: Be mat ma ap suat tai moi iem tren o bang hang so.Phng trnh:

-> Ho cac mat phang nam ngang

3. LU CHAT TNH TRONG TRNG TRONG LC (3/8)c. Ap lc thuy tnh tren dien tch phang+ o ln:Xet dien tch dS, tai trong tam:

Ap lc tren toan bo dien tch S:

+ iem atXet trng hp p0=0Vi phan moment cua ap lc oi vi truc quay Ox:Moment cua ap lc tren toan bo dien tch S oi vi truc quay Ox:

Moment tnh theo ap lc P:

3. LU CHAT TNH TRONG TRNG TRONG LC (4/8)T (*) va (**) suy ra iem at lc D:

o lech tam lc:

Trng hp p00: oi thanh bai toan tng ng e giai

Trong o

3. LU CHAT TNH TRONG TRNG TRONG LC (5/8)+ Tnh ap lc thuy tnh bang pp o th:Bieu o ap lc: la o th bieu dien phan bo ap suat p/ tren dien tch phang.Xet dien tch dS, tai trong tam:

o ln cua ap lc tren toan bo dien tch S:

va P i qua trong tam CV cua the tch V (khong phan biet p0 bang hay khac 0)Trng hp S la hnh ch nhat co canh song song vi mat thoang:

va P i qua trong tam C( - dien tch bieu o ap lc)

3. LU CHAT TNH TRONG TRNG TRONG LC (6/8)d. Ap lc thuy tnh tren dien tch congXem xet trng hp ap suat tren mat thoang bang ap suat kh tri.Ba hnh chieu cua S: Sx, Sy, SzXet vi phan dien tch dS, tai trong tam:

Ap lc tren toan bo dien tch S:

Phan tch:

3. LU CHAT TNH TRONG TRNG TRONG LC (7/8)Thanh phan ap lc tren truc toa o x

=> thanh phan ap lc tren truc x chnh bang ap lc thuy tnh tren dien tch phang Sx:

Tng t cho thanh phan ap lc tren truc toa o y:Thanh phan ap lc tren truc toa o z:

(W the tch vat ap lc)iem at lc?

3. LU CHAT TNH TRONG TRNG TRONG LC (8/8)e. Lc ay ArchimedeXet vat co the tch V chm trong chat longXet vi phan the tch dV hnh lang tru thang ng. No co 2 be mat tren va di tiep xuc vi chat long va thanh phan ap lc tren phng truc z tac dung tren 2 be mat nay la: dPz1 va dPz2.Ap lc tong cong tac dung len dV theo truc z:

Thanh phan ap lc tren truc z tac dung len toan bo be mat bao boc t.tch V:

Tng t, tnh c 2 thanh phan ap lc tren 2 truc con lai:

4. TNH TNG OI (1/2)4.1 Chat long tnh trong thung cong thang vi gia toc khong oi.Vector cng o lc khoi:

Cac thanh phan cua tren cac truc to:

=> Phng trnh cua ap suat thuy tnh:

Nhan xet:Mat ang ap:-> Ho cac mphang nghieng goc

Tren mat phang x=const:

4. TNH TNG OI (2/2)4.2 Chat long tnh trong thung cong quay tron eu.Vector cng o lc khoi:

Cac thanh phan cua tren cac truc to:

=> Phng trnh cua ap suat thuy tnh:

Nhan xet:Mat ang ap:-> Ho cac mat cong paraboloid tron xoay

Tren mat tru r=const:

Chng 3. ONG HOC LU CHATHai phng phap mo ta chuyen ong cua lu chatCac khai niemPhan loai chuyen ongGia toc toan phan cua phan t lu chatPhng trnh lien tucPhan tch chuyen ong cua phan t lu chat

1. HAI PHNG PHAP MO TA CHUYEN ONG (1/2)1.1 Phng phap Lagrange.Chuyen ong cua the tch lu chat c mo ta bi quy ao cua cac phan t cua the tch:

u iem: mo ta chuyen ong mot cach chi tiet.Khuyet iem: so lng phng trnh phai giai qua ln (3n); khong the mo ta cung mot luc quy ao cua nhieu phan t.Kha nang ap dung: phong th nghiem.

1. HAI PHNG PHAP MO TA CHUYEN ONG (2/2)1.2 Phng phap Euler.Chuyen ong cua the tch lu chat c quan niem la trng van toc va c mo ta bi mot ham van toc lien tuc theo khong gian va thi gian:

u iem: ch co 3 phng trnh.Khuyet iem: khong cho thay ro cau truc cua chuyen ong.Kha nang ap dung: tnh toan.

=> PHNG PHAP S DUNG: EULER

2. CAC KHAI NIEM (1/2)2.1 ng dong.ng dong La ng cong vach ra trong lchat chuyen ong sao cho vector van toc cua cac phan t lu chat chuyen ong tren o tiep tuyen vi no.Co the thay oi theo thi gian.Phng trnh

2.2 Ong dong, dong chay.Ong dong la be mat dang ong tao bi vo so cac ng dong cung i qua mot chu vi khep kn.Dong chay la khoi lng lchat chuyen ong ben trong ong dongV du: mat trong cua ng ong; be mat long song cung vi mat thoang la cac ong dong .

2. CAC KHAI NIEM (2/2)2.3 Mat cat t, chu vi t, ban knh thuy lc.Mat cat t (A) la mcat ngang dong chay sao cho trc giao vi cac ng dong va nam ben trong ong dong.Chu vi t (P) la phan chu vi cua mcat ni dong chay tiep xuc vi thanh ran (0).Ban knh thuy lc (R)

2.4 Lu lng, van toc trung bnh mcat.Lu lng (Q) la the tch lchat chuyen ong ngang qua mcat t trong mot v thi gian.Van toc trung bnh mcat (V):

3. PHAN LOAI CHUYEN ONG (1/2)Theo anh hng cua o nht:Chuyen ong cua lu chat ly tng ( = 0)Chuyen ong cua lu chat thc ( 0)Theo anh hng cua khoi lng rieng:Chuyen ong cua lu chat khong nen c ( = const)Chuyen ong cua lu chat nen c ( = var)Theo anh hng cua thi gian:Chuyen ong cua lu chat la on nh ( )Chuyen ong cua lu chat la khong on nh ( )Theo khong gian cua chuyen ong:Chuyen ong cua lu chat la 1 chieu (u 0; v = w = 0)Chuyen ong cua lu chat la 2 chieu (u 0; v 0; w= 0)Chuyen ong cua lu chat la 3 chieu (u 0; v 0; w 0)

3. PHAN LOAI CHUYEN ONG (2/2)Theo trang thai chay:Chuyen ong tang: la trang thai chay ma o cac phan t lu chat chuyen ong trt tren nhau thanh t tang, tng lp, khong xao tron lan nhau.Chuyen ong roi: la trang thai chay ma o cac phan t lu chat chuyen ong hon loan, cac lp lu chat xao tron vao nhau.Th nghiem Reynolds

4. GIA TOC TOAN PHAN CUA PT LU CHAT (1/1)Xet phan t lu chat chuyen ong tren quy ao cua no (dung bien Lagrange), gia toc cua pt :

Trong bien Euler, van toc la ham theo khong gian va thi gian -> van toc u c tnh theo u0 bang chuoi Taylor:

Thay vao bieu thc gii han:

va thc hien phep tnh gii han:

5. PHNG TRNH LIEN TUC (1/2)2.1 Phng trnh lien tuc.nh luat bao toan khoi lng: toc o gia tang cua khoi lng cua mot he vat chat bang khoi lng chuyen ong vao he trong 1 n v thi gian.Ap dung cho lu chat trong the tch kiem soat:Klng lu chat trong the tch:

Klng lchat cong ra khoi the tch:

Theo L bao toan:

oi vi lu chat khong nen c, =const:

5. PHNG TRNH LIEN TUC (2/2)2.2 Phng trnh lien tuc cho dong chay on nh cua lc khong nen c.Xet the tch kiem soat la oan dong chay gia hai mcat 1-1 va 2-2Trong trng hp lu chat khong nen c, chuyen ong on nh ptrnh lien tuc di dang tch phan c rut gon con:

Chia dien tch bao boc S = A1 + A2 + SnTach tch phan thanh tong cua 3 tch phan:

Hai tch phan au cho lu lng ngang qua cac mcat 1-1 va 2-2, con tch phan th 3 bang khong:

6. PHAN TCH CHUYEN ONG CUA PHAN T LU CHAT (1/4)Xet pt lu chat. iem M0 c chon lam cc cua pt.Gia s van toc tai M0 a biet, cau hoi la van toc tai iem M?S dung chuoi Taylor, bo qua so hang vo cung nho bac cao, tphan van toc ux:

Cong va tr so hang vao ve phai cua bieu thc tren, sau o sap xep lai se thu c bieu thc:

6. PHAN TCH CHUYEN ONG CUA PHAN T LU CHAT (2/4)at:

Thanh phan van toc ux se c tnh bang cong thc:

Tng t:

Y ngha cac so hang:+ x: Gia s mat trai va mat phai cua pt ch chuyen ong theo truc x vi van toc u0x va ux tng ng cua iem M0 va M. Do co s chenh lech van toc, sau 1 n v thi gian, pt dai ra mot oan la: ux-u0xDo o toc o gian dai tng oi cua pt la:

6. PHAN TCH CHUYEN ONG CUA PHAN T LU CHAT (3/4)Khi x 0, ta co:

i - toc o gian dai tng oi cua pt theo truc xi.+ z va z : Gia s mat tren va mat di cua pt ch chuyen ong theo truc x vi van toc u0x va ux tng ng cua iem M0 va M. Do co s chenh lech van toc, sau 1 n v tgian, pt se b o nghieng vi goc:

Tng t, do co s chenh lech thanh phan van toc tren phng y gia mat trai va mat phai ma pt cung se b o nghieng vi goc:

6. PHAN TCH CHUYEN ONG CUA PHAN T LU CHAT (4/4)Neu ca 2 chuyen ong ong thi xuat hien, pt se b thay oi nh hnh:Trong 1 n v thi gian pt b bien dang mot goc:

k - toc o bdang goc cua pt quanh truc xk.Trong 1 n v thi gian pt quay i mot goc:

k - toc o quay cua pt quanh truc xk.nh ly Hemholm: Cong cua pt lu chat bao gom cong cua vat ran (theo cc va quay quanh cc) va cong bien dang (bdang dai va bdang goc).Vector quay van toc:

Chng 4. ONG LC HOC LU CHATPhng trnh vi phan chuyen ong cua lu chatPhng trnh nang lngTch phan phng trnh EulerPhng trnh Bernoulli cho dong chay cua l chat thcPhng trnh bien thien ong lng

1. PHNG TRNH VI PHAN C.ONG CUA LU CHAT (1/3)1.1 Phng trnh Euler cho chuyen ong cua lu chat ly tng.Lu chat ly tng: =0 =0 khai niem ap suat: Ngoai lc tac dung len phan t trenphng x:Lc khoi:

Lc mat:

Phng trnh nh luat II Newton tren phng x cho phan t =>

Tng t:

hay

1. PHNG TRNH VI PHAN C.ONG CUA LU CHAT (2/3)1.2 Phng trnh Navier-Stokes cho chuyen ong cua lu chat thc.Lu chat thc: 0 0 Ngoai lc tac dung len phan t trenphng x:Lc khoi:

Lc mat:

Viet phng trnh nh luat II Newton tren phng x cho phan t =>

Gia thiet Stokes:

vi

1. PHNG TRNH VI PHAN C.ONG CUA LU CHAT (3/3)a ti phng trnh Navier-Stokes tren truc x:

Di dang vector:

oi vi lu chat khong nen c:

Lu y gia toc c tnh:

2. PHNG TRNH NANG LNG (1/2)2.1 Phng trnh van tai nang lng:nh luat bao toan nang lng (L th nhat cua nhiet ong lc hoc): Toc o bien thien cua ong nang va noi nang bang tong cong c hoc cua ngoai lc va cac dong nang lng khac tren 1 n v thi gian

e: noi nang (kh ly tng: ; chat long khong nen: ) : dong nhiet rieng i vao qua be mat bao bocnh luat truyen nhiet Fourier:Bien oi:

Thu c:

2. PHNG TRNH NANG LNG (2/2)2.2 Phng trnh van tai ong nang:Ptrnh Navier di dang tensor:

Nhan ptrnh tren cho ui :

2.3 Phng trnh van tai noi nang:Tr ptrnh van tai nang lng cho ptrnh van tai ong nang:

S dung gia thiet Stokes va cho lu chat khong nen c:

LI GII S CA PT NAVIER-STOKESLu cht nn c:Dng bao cch NACA 0012

LI GII S CA PT NAVIER-STOKESLu cht khng nn c: Dng tia ln thnh cng

3. TCH PHAN PHNG TRNH EULER (1/5)Phng trnh Euler dang Lambo-Gromeko:

Gia thiet: = const Phng trnh Euler dang Lambo-Gromeko thanh:

3. TCH PHAN PHNG TRNH EULER (2/5)3.1 Trng hp chuyen ong co the.Chuyen ong co the: va Phng trnh Euler tren thanh:

Trong trng trong lc: U = - gz(Tphan Lagrange)oi vi chuyen ong on nh:

3. TCH PHAN PHNG TRNH EULER (3/5)3.2 Trng hp lu chat chuyen ong on nh, tphan doc ng dong.Lay vi phan chieu dai ng dong:Nhan vo hng no vi pt. Euler:

Rut ra:

Trong trng trong lc: U = - gz(Ptrnh Bernoulli)

3. TCH PHAN PHNG TRNH EULER (4/5)3.3 Trng hp lu chat chuyen ong on nh, tphan theo phng vuong goc vi ng dong.Phng trnh Euler trong he toa o t nhien:

Lay vi phan chieu dai ng phap tuyen vi ng dong:Nhan vo hng no vi pt. Euler:

Khi R :

Trong trng trong lc: U = - gz(Tphan Euler)

3. TCH PHAN PHNG TRNH EULER (5/5)Yngha nang lng cua cac so hang tch phan.Xet pt Bernoulli. Qua trnh thiet lap qua cac bc:

Cac so hang:

Phng trnh Bernoulli la pt bao toan nang lng

4. PTRNH BERNOULLI CHO DONG CHAY LU CHAT THC (1/2)Xet oan dong chay on nh nam gia 2 mcat t 1-1 va 2-2.Xet 1 ng dong trong oan dong chay. Neu cho rang lu chat la ly tng, ptrnh Bernoulli cho ng dong:

Phng trnh tren the hien tnh bao toan. Neu lu chat la thc th:

Bay gi xet 1 dong chay nguyen to. Nang lng cua no bien oi theo ptrnh:

Nh vay cho toan bo dong chay, nang lng cua no se bien oi theo ptrnh:

4. PTRNH BERNOULLI CHO DONG CHAY LU CHAT THC (2/2)Thc hien cac tch phan:

Thay vao cho ket qua:

Ghi chu:1. ieu kien ap dung pt Bernoulli cho dong chay: ; =const; Tai hai mcat ap dung pt, dong chay phai la bien oi cham.Trong oan dong chay gia 2 mcat, khong co nhap lu hoac tach lu.2. Neu trong oan dong chay gia 2 mcat viet pt co turbine, may bm:

5. PHNG TRNH BIEN THIEN ONG LNG (1/2)5.1 Phng trnh bien thien ong lng.Nguyen ly bien thien ong lng: toc o bien thien cua ong lng cua mot he vat chat bang vector tong ngoai lc tac dung len he.Ap dung cho lu chat trong the tch kiem soat:

Bien oi:

oi vi dong chay on nh, ptrnh bien thien ong lng la:

5. PHNG TRNH BIEN THIEN ONG LNG (2/2)5.2 Ptrnh bien thien lng cho dchay on nh cua lc khong nen c.Xet the tch kiem soat la oan dong chay gia hai mcat 1-1 va 2-2Chia dien tch bao boc S = A1 + A2 + SnPtrnh bien thien ong lng thanh:

Tch phan th 3 bang khong con hai tch phan au c viet lai thanh:

Cac tch phan nay c thc hien:

Thay vao cho ket qua:

Chng 5. DONG CHAY ON NH TRONG ONG CO APCac khai niemPhng trnh c ban cua dong chay euTon that cot ap doc ngTon that cot ap cuc boTnh toan thuy lc ng ong

1. CAC KHAI NIEM (1/2)1.1 Hai trang thai chay.Chay tang: ReD 2300Chay roi: ReD > 2300

1.2 Mo hnh BoussinesqPhan tch Reynolds:

( - van toc trung bnh thi gian; u van toc mach ong)Mo hnh Boussinesq:Van toc tnh toan la van toc trung bnh thi gian.Lu chat trong chuyen ong roi co o nht la o nht hieu dung: (t o nht roi)Mo hnh Prandtl (1925)

1. CAC KHAI NIEM (2/2)1.3 Lp mong chay tang.

> -> che o chay thanh trn thuy lc -> che o chay thanh nham thuy lc

2. PHNG TRNH C BAN CUA DONG CHAY EU (1/2)2.1 Phng trnh c ban.Ngoai lc tac dung tren phng chuyen ong:Gs = lAsin - trong lcP1 - P2 = (p1- p2)A ap lcFms = 0lP lc msat tren vo ongPtrnh bthien lng tren phng s:

Ptrnh Bernoulli cho oan dong chay t mc 1-1 -> mc 2-2:

T (1) va (2) =>

2. PHNG TRNH C BAN CUA DONG CHAY EU (2/2)2.2 Li giai.Xet mat tru ban knh r, ptrnh c ban cua dong eu:

a) Chay tang.

b) Chay roi.Xet mat tru ban knh r sat thanh ong, r R0:

Tch phan cho ket qua:

3. TON THAT COT AP DOC NG (1/4)3.1 Cong thc Darcy.T phng trnh c ban cua dong eu rut ra:

ng suat ma sat c xac nh bang thc nghiem:

Thay 0 t (2) vao (1), rut ra:

- he so ton that cot ap doc ng hoac he so ma sat ng ong c xac nh bang thc nghiem vi:hoac cho ong tron(1)(2)

3. TON THAT COT AP DOC NG (2/4)Th nghiem Nikurade (1933):

Cac cong thc thc nghiem- Chay tang (ReD < 2300):

- Chay roi (ReD > 4000):

(Colebrook-1939)(Altsun-?)

3. TON THAT COT AP DOC NG (3/4)- o th Moody (1944):

0,000 01

1

2

3

4

5

7

x10

3

1

2

3

4

5

7

x10

4

1

2

3

4

5

7

x10

5

1

2

3

4

5

7

x10

6

1

2

3

4

5

7

x10

7

1

x10

8

0,000 005

0,000 007

0,000 05

0,000 1

0,000 2

0,000 4

0,000 6

0,001

0,002

0,004

0,006

0,008

0,01

0,015

0,02

0.03

0,04

0,05

0,008

0,009

0,01

0,015

0,02

0,025

0,03

0,04

0,05

0,06

0,07

0,08

0,09

0,1

Khu chay roi thanh nham hoan toan (Khu sc can bnh thng)

Khu

Chay tang

Khu chay roi

thanh nham

Khu chay roi

thanh trn

Khu chuyen tiep

Re =(VD/(

D

(

O TH MOODY

3. TON THAT COT AP DOC NG (4/4)3.2 Cong thc Chezy.Cong thc Chezy:

So sanh vi cong thc Darcy:

So Chezy thng c tnh theo cong thc Manning:

Cac cong thc suy dien t Chezy:(C - So Chezy)(n - he so nham Manning)(K module lu lng)

4. TON THAT COT AP CUC BO (1/1)4.1 Khai niem.

Trong oan lm:

4.2 Cong thc Darcy - Weisbach

( - he so ton that cot ap cuc bo)

5. TNH TOAN THUY LC NG ONG (1/4)5.1 Gii thieu.Cac phng trnh, cong thc c ban:Ptrnh Bernoulli cho dong chayPtrnh lien tucCac cong thc tnh ton that cot ap (ton that cot ap doc ng va cuc bo)Cac gia thiet:lm

5. TNH TOAN THUY LC NG ONG (2/4)5.2 Cac bai toan.a. ng ong ngan ve mat thuy lc.Ch xet ng ong n gianXem bai toan tong quat. Ptrnh Bernoulli t mcat 1-1 ti mcat 2-2:

a ti:

vi

T ptrnh tren neu cho Q se tnh c H, hoac ngc lai neu cho H se tnh c Q

5. TNH TOAN THUY LC NG ONG (3/4)b. ng ong dai ve mat thuy lc.b1. ng ong n gianXem bai toan tong quat. Ptrnh Bernoulli t mcat 1-1 ti mcat 2-2:

a ti:

T ptrnh tren neu cho trc 2 trong so 3 thong so Q, H va HB, se tnh c thong so con lai.

5. TNH TOAN THUY LC NG ONG (4/4)b2. ng ong gan noi tiep

Trong tnh toan c thay the bang 1 ong tng ng vi:

b3. ng ong gan song song

Trong tnh toan c thay the bang 1 ong tng ng vi:

Chng 6. CHUYEN ONG CO THE 2 CHIEU Cac khai niemCac chuyen ong the phang n gianChong chap cac chuyen ong the

1. CAC KHAI NIEM (1/2)1.1 Chuyen ong co the.n: Cong cua lu chat c goi la co the khi ton tai mot ham sao cho:

- ham the van toc; ng cong (x,y) = const ng ang the Tnh chat:

Phng trnh:

1.2 Ham dong.n: Ham (x,y) sao cho c goi la ham dong. ng cong (x,y) = const ng dong Tnh chat:

Phng trnh:

1. CAC KHAI NIEM (2/2)1.3 Ham the phc.Ham dong va han the co tnh trc giao do:

=> mo ta bang ham the phc:

Cac ai lng:

1.4 Tnh chong chat.

2. CAC CHUYEN ONG THE PHANG N GIAN (1/2)2.1 Chuyen ong thang eu.

U0 van toc dong chay

2.2 iem nguon va gieng

q - lu lng n v

2. CAC CHUYEN ONG THE PHANG N GIAN (2/2)2.3 Xoay t do.

- lu so van toc

2.4 Lng cc.

m - moment cua lng cc

3. CHONG CHAP CAC CHUYEN ONG THE (1/2)3.1 Chuyen ong bao ban vat.

(dong thang eu + nguon)

3.2 Chuyen ong bao vat Rankine.

(dong thang eu + nguon + gieng)

3. CHONG CHAP CAC CHUYEN ONG THE (2/2)3.3 Chuyen ong bao tru tron.(dong thang eu + lng cc)

3.4 Chuyen ong bao tru tron co lu so van toc

(dong bao tru tron + xoay t do)